1. Field of the Invention
The present invention pertains to the fields of radio wave communications and oscillators. More particularly it pertains to plural active antennas driven by plural parallel connected oscillators.
2. Description of the Prior Art
IMPATT diodes are well known as a solid-state source of microwave energy. However, each IMPATT diode outputs relatively little power and the outputs of similar diodes are incoherent and at different frequencies. Heretofore, the output of a number of diodes, typically, has been provided by a relatively inefficient and bulky combiner which also provides for frequency control by injection locking from a separate source.
If an antenna array is powered by IMPATT diodes, either the array elements can be driven by a single such combiner through a relatively bulky and inefficient branching feed, or a diode may be relatively directly connected to each element. In the latter arrangement injection locking is provided from a single source and distributed to each diode, typically through circulators individual to the diodes, so that a relatively bulky and complex branching feed is not avoided.
Since arrays are typically used becuse they provide a steerable beam and since it is, ultimately, desired to provide large integrated circuit arrays of planar configuration, it is highly desirable that any arrangement for driving an array from a plurality of diodes be adapted for beam steering and be adaptable for use in such a configuration, particularly by elimination or simplification of signal distribution networks and by elimination of circulators which cannot be deposited by the usual integrated circuit making techniques.